This invention is an improvement on the device described in U.S. Pat. No. 3,819,251, issued June 25, 1974, for a Double Clip Lettering Guide.
The above-referenced lettering guide utilizes a double clip member which has a fixed angle between one clip adapted for holding a transparent window card and a second clip for holding an image-producing card. When the angle between the window card and the image-producing card equals the angle between the window card and the drawing surface plane upon which the letterint guide rests, the image from the image-producing card is reflected upon the drawing surface plane. It was found that the necessary angular precision could not be achieved by dies produced from machine stamping processes. This, in turn, requires difficult and time consuming hand adjustment of the double clip members. Also, the use of image-producing cards and tinted window cards of various thicknesses causes distortion of the positions of the clips which results in variations in the fixed angle between the two clip members. Furthermore, mounting and assembly of the lettering guide on a drafting machine and the repeated use of the device causes slight angular distortions. The distortions in the fixed angle result in reflection of the image above or below the plane of the drawing surface limiting the usefulness of the lettering guide.
It is an objective of the present invention to provide for the adjustment of the angle between the two clip members in the double clip lettering guide by providing an adjustment wedge which can vary the angle between the two clip members.